In a conventional temperature and humidity adjusting apparatus, a heat pump may be employed for temperature adjustment and a pot type humidifier may be employed for humidification.
On the other hand, as a method for precisely controlling the temperature and humidity adjusting apparatus, temperature and humidity are controlled on the basis of an air temperature and a relative humidity at a temperature and humidity adjusting air outlet of the temperature and humidity adjusting apparatus to obtain air having a predetermined temperature and humidity at the outlet.
On the other hand, in the conventional control method, precision of the humidifier cannot be high enough. Namely, since the humidifier does not permit delicate control, humidity at an outlet of a cooling and dehumidifying portion is once lowered to be much lower than a set humidity, and then humidity for the difference to the set humidity is added by a humidifier to obtain a predetermined humidity.
However, in the above-mentioned conventional temperature and humidity adjusting apparatus, a compressor has to be employed for the heat pump and so forth. Therefore, the temperature and humidity adjusting apparatus inherently becomes bulky and possibly generates vibration. Also, difficulty arises due to fluorocarbons being employed in the compressor. Furthermore, since the pot type humidifier is employed, humidity response speed is low.
Also, in the conventional control method, since control is performed depending upon relative humidity, humidification control has to be performed while constantly monitoring temperature variation. Accordingly, adjusting the temperature and humidity of the air at the outlet to set values may take a long time.
On the other hand, the amount of energy required for cooling and dehumidification may become substantially large, which is contrary to desires for energy conservation. Furthermore, under certain conditions, water may condense on the apparatus and freeze.
As a solution for these problems, when temperature and humidity control are performed on the basis of absolute humidity, a concrete method for deriving the absolute humidity from the relative humidity becomes necessary. Also, since control on the basis of the absolute temperature uses a shorter time period to reach the target temperature and humidity than control on the basis of the relative humidity, a more responsive humidifier becomes necessary.
Also, precisely controlling the humidity without lowering the absolute humidity of the air at the outlet of the cooling and dehumidifying portion below the absolute humidity setting requires that the cooling and dehumidifying portion and the humidifier be precisely controllable.
Therefore, it is an object of the present invention to provide a temperature and humidity adjusting apparatus which can be more compact and lighter weight in comparison with the conventional apparatus and free of vibration, and furthermore can improve respective precision in temperature control and humidity control.
Another object of the present invention is to provide a control method which can quickly and precisely reach a temperature and humidity setting that saves energy, permits precise control with less performance required from the cooling and dehumidifying portion and permits further reduction in the size of the apparatus.